The invention relates to a method for the electrochemical treatment of metal workpieces, in particular of their flow channels, by means of a tool inserted into the flow channel and an electrolyte flow between the tool and the wall of the flow channel.
Such method is known from DE 40 40 590 C1. Subject matter of the known method is the continuous measurement of the electrical voltage at the working gap between tool and workpiece, wherein with increasing gap width due to the erosion of the material, the operating current is increased in order to reduce the work time. In such method it has already been suggested to make the end of the working process dependent on attaining a nominal final voltage at the working gap. Since according the known method, the operating current during the treatment procedure is to be raised continuously, for the regulation of the current increase a physical variable has been suggested which varies with increasing size of the working gap. In the simplest case, as the physical variable the gap voltage is addressed there. Alternatives are the throughflow volume and the pressure of the electrolyte.
When deburring workpieces which comprise narrow flow channels, in particular nozzle bodies with intersecting bores, the suitable length of time of treatment for the removal of the burrs is determined in several test runs. But no calibration can be achieved with this method.
The result is that in spite of constant electrochemical treatment, tolerances on the order of magnitude of 8% of the nominal throughflow, are present. Each individual nozzle must subsequently be calibrated with test oil under high pressure wherein the actual oil throughflow is measured. Depending on the measured values, the nozzle bodies are subsequently divided into different tolerance groups.